Advancements in solid-state lighting have enabled a light-emitting diode (LED) to switch to different light intensity levels at a rate which is fast enough to be imperceptible to the human eye. Therefore, this functionality can be used for visible light communication (VLC) where data is encoded in the emitting light in various ways.
A photodetector (a.k.a., a light sensor or a photodiode) or an image sensor (e.g., a matrix of photodiodes) is able to receive modulated optical signals and decode the data therein. As such, LEDs are able to serve the dual purpose of providing illumination and facilitating the communication of data.